PSO25 is a standard SAP Structure so does not store data like a database table does. It can be used to define the fields of other actual tables or to process "Data elements for reports" Information within sap ABAP programs. This is done by declaring abap internal tables, work areas or database tables based on this Structure. These can then be used to store and process the required data appropriately. i.e. DATA: wa_PSO25 TYPE PSO25.
The PSO25 table consists of various fields, each holding specific information or linking keys about Data elements for reports data available in SAP. These include FMKWTA0002 (Test run), FMKWTA0003 (Detail list), FMKWTA0004 (Issue Accounts), FMKWTA0005 (Issue Documents)... See below for full list along with technical details, documentation, text table, check tables, foreign key relationships, conversion routines, relevant tcodes and example ABAP select code etc. .